Miscellany

Having returned from dinosaur hunting basically intact, I’d like to explain a little of the process that is actually involved. Also very interesting, of course, would be to talk about the dinosaurs themselves, and what we hope to learn by studying them. But that’s another huge subject, which I am fairly unqualified to talk about, so you’d do better to hunt about on the web (or visit a museum). What I can try to do is give you an idea of what it is like to actually go out there and dig up some bones.

In particular, there are two questions I’ve always had about the nuts and bolts of paleontology: how do you actually find the fossils in the first place, and how to you dig them out once found? Answer in both cases: a little bit of know-how, and a huge amount of effort.

This is the second year I’ve gone to Wyoming with Project Exploration; last year I did manage to find a fossil myself, but this year we focused more on digging than on prospecting for new specimens. The prospecting was done ahead of time by Paul Sereno and some of his students. (Paul is the paleontologist half of the husband-and-wife team who founded PE; Gabrielle Lyon is the educator half.) The relevant know-how, as best I can make out, involves a combination of geological background and word of mouth. In fact, it seems from my outsiders perspective that there isn’t much of a bright line separating the disciplines of geology and paleontology; each relies heavily on knowledge from the other field, and experts in one are typically well-versed in the other. For dinosaur-hunting purposes, the geology comes in once you realize that your prospecting efficiency is greatly enhanced if you spend your time peering at rocks that actually date from the Mesozoic (the dinosaur era, between 248 and 65 million years ago), rather than before or after. Not only that, but you would especially like to have a layer that has been uplifted by geological activity, so that exposed rock faces (out of which might be sticking dinosaur fossils) are plentiful. Formations of this sort are common in certain areas of the Rocky Mountains, which is one reason why this region has produced so many significant dinosaur finds. We were working in the Morrison Formation, a limestone bed dating from the Jurrasic. (The Mesozoic is divided into three periods: the Triassic [248-108 Mya], the Jurassic [208-146Mya], and the Cretaceous [146-65 Mya].) The Morrison has long been a prolific source of dinosaur fossils. Here is a picture of the layered topography through which we were poking around; click for a bigger view.

Word of mouth comes in for the simple reason that, once you find a dinosaur somewhere, the surrounding regions are (sensibly) thought to be more likely to contain fossils than other randomly-chosen regions of the countryside. Not only that, but much of the land in this region of Wyoming is owned by ranchers who know the terrain like the back of their hand, and have become adept at spotting fossils. So sometimes it’s as simple as being told by a local rancher that there are some interesting-looking fossils at a certain site, or at least that a certain region seems promising.

In this particular case, Paul and some of his students had visited some formations around Shell, Wyoming (pop. approx. 50) a few weeks before we went for our expedition. They found some interesting fossils the old-fashioned way: waking up early in the morning and spending their days walking for miles, paying close attention to every rock that was part of the relevant geological layer. Fossils, of course, are bones (or other parts of an organism) that have been preserved in rock, and the process of fossilization typically involves much of the original organic material actually being replaced by rock. Which is to say, the fossils look awfully rock-like. So you have to know what you are doing, and long practice is at least as important as being told ahead of time what to look for. (Most common sentence heard at these digs, spoken by we amateurs to one of the people who knew what they were doing: “Is this a bone?”) Once you’ve seen some examples, you begin to recognize the striations characteristic of fossilized bone marrow, in contrast with the relative smoothness or unstructured graininess of rock. Still, wandering through long stretches of hillside, you need to have an eagle eye to be effective at prospecting.

In addition to a few dinosaur fossils, they found the trunk of a tree from the Jurassic that was over five feet wide; if it continues into the rock in which it is embedded, it may very well be over forty feet long. Paul calculated that two semi trucks should be able to haul the thing back to Chicago, where it could be used as part of an exhibition for PE of dinosaurs in their native habitat. At the same time, by looking at the interior we could learn something about the climatological conditions at the time the tree was alive (over perhaps a century or two). Personally, I’m happy to spend my time doing the delicate work of digging out dinosaur bones, and not having to be responsible for a several-ton fossilized tree.

The areas in which one finds these specimens are what most of us would describe as the middle of nowhere. Once you’ve found an interesting site, you mark its location in the handheld GPS unit that you remembered to bring with you while prospecting, so that you can actually find the thing when you come back. (Don’t ask me what they did before GPS.) There is also the worry that someone else comes along and digs up the fossil that you have found (expeditions like ours take place largely on government land, maintained by the Bureau of Land Management, so in principle anyone can come and dig them up, so long as they get a government permit to dig). So after finding a fossil and perhaps doing some preliminary digging to verify that it’s worth a follow-up visit, you then take a shovel and cover it back up with dirt so that it’s not obvious to future visitors. It’s not even obvious to you when you come back some time later, so a certain amount of time is spent re-finding the sites that were found on a previous visit.

Tomorrow: we go out and actually dig up some bones.

In the Denver airport on the way back from Wyoming, I used one of the public terminals to check email etc. (I haven’t completely mastered the wireless setup on my new laptop.) Of course I stopped by Preposterous to check on how things were going. Or at least I tried; the site was blocked for containing inappropriate content. Still trying to think what might have set that off. Questioning Einstein, maybe?

I am back from the wilds of Wyoming, having happily scampered through the Jurassic for a few days. A full report will be forthcoming. But first I wanted to thank Gretchen for filling in while I was gone; hopefully she will post again in the future.

A lot can happen in one short week, so I just wanted to hit some high points of the events you had to endure without me.

• The big news, my man Barack Obama hit a home run at the convention. I didn’t get a chance to see the speech, which I hear was not even broadcast by the networks. Also we were staying at a ranch owned by folks who were quite hospitable, but whose politics didn’t really align with mine. The first clue was the large painting of Jesus kneeling in front of the Liberty Bell. I must have missed that chapter in the Gospels. So Democratic-convention-watching wasn’t one of the scheduled activities.
• But actually, is the lack of coverage by the networks worth all of this hand-wringing? Don’t most people have cable TV by now, and don’t the cable networks cover the thing to death? I never understood why there was supposed to be a moral imperative for all three networks to provide essentially the exact same pictures. They could just rotate, like with the Olympics (without the dizzying rights fees).
• Despite the Dems having apparently stage-managed the convention quite skillfully, the free speech zones are a travesty. (Images found linked at Majikthise.) Their existence is a travesty on basic philosophical grounds, but their appearance is a disaster purely on craven political grounds. I mean, barbed wire?
• In one last bit of Hawkingiana, it’s worth pointing to this statement by John Preskill about the bet he won with Hawking (found linked at Michael Nielsen’s blog). Poor Preskill, who is a world-class theoretical physicist in his own right, but can only get in the newspapers by winning bets with Hawking.
• Francis Crick passed away. Most of what I know about Crick comes from reading The Double Helix, which I’m sure isn’t the most reliable source. More discussion at the Panda’s Thumb.
• Atrios unmasked! With his permission. (That’s the mysterious Atrios of Eschaton, for you scientists out there.)
  
• Finally, let’s give some props to Allen Iverson of my beloved Philadelphia 76ers, one of only two NBA stars (along with Tim Duncan) to fulfill his initial obligation to go to Greece as part of the Olympic team. Iverson has his issues, but he has always been treated far worse than he deserved, just because of his hairstyle and tattoos. Now he’s the co-captain of the Olympic team, which has to feel good.

I’m sure other interesting things “happened,” but if I wasn’t paying attention to them, how real can they be?

I wanted to mention why I will be in Wyoming next week: I’ll be hunting dinosaurs. (Fortunately they will have been dead for millions of years, otherwise it would not really be a fair fight.)

I’ve blogged previously about the great work that Gabe Lyon and Paul Sereno do through Project Exploration, a non-profit organization devoted to bringing the excitement of science to city kids. Doing good work requires money, so PE has to devote a lot of energy to fund-raising, and has been blessed with a devoted and enthusiastic set of donors. One thing they like to do each year is to take a trip with some of the donors to do some honest fossil excavation at a site in the U.S — sifting for microfossils, prospecting for larger dinosaur bones, and gently digging up and preserving the major fossils that have been found. (One goal is to build a teaching collection for the University.) So, while the expedition is fun and certainly educational, it’s also quite serious; those are the bones of an actual Tyrannosaur that you are digging up and perhaps breaking in pieces if you’re not too careful.

All of this seems perfectly sensible; less clear is how they got the idea that it would be amusing to bring along a cosmologist. But far be it from me to ask questions. (I did check that they wouldn’t expect me to be able to identify constellations in the night sky, but they said that was okay.) I went last year, had a great time, even found a serious fossil myself. (A hadrosaur, if you must know — the “cattle of the Cretaceous,” a major contributor to T-Rex’s diet.) And I’m going again this year. I’ll report on any major discoveries when I get back.

Update: Here is the post-expedition report, part one and part two.

Enough talking about Hawking, I would think. There are a bunch more newspaper stories out there (including these from Newsday and the New York Times that were nice enough to quote me). Also, Juan Maldacena and I appeared together today on Odyssey, the program hosted by the very same Gretchen Helfrich who will soon be our official guest-blogger. No quid-pro-quo was involved, I promise. You are welcome to listen to the program if you have RealAudio.

Just to show you that scientists don’t always agree, two representative quotes. First, Leonard Susskind in the Times:

Until Stephen’s recent reversal, he was about the only person still getting it wrong.

Susskind is a string theorist who thinks that it’s already been figured out, nothing to see here, time to move on. Next, from my colleague Bob Wald:

Hawking is completely revising his prior belief that what goes into a black hole is washed out. Now he believes that anything emitted from a black hole can be identifiable back to its source. He’s running away from what we still believe.

Wald is a general-relativist, quite skeptical about the claimed mechanisms for getting the information out. This is the problem with thought-experiments; they’re not nearly so conclusive as actual experiment-experiments.

As anticipated, Stephen Hawking gave his talk on black hole information loss at the GR17 conference in Dublin today; newspaper stories are already popping up, although they don’t tell us much we didn’t already know. I’ll try to have some incisive commentary soon; in the meantime, why not just get right to the heart of the matter? Here are the press release and transcript for Hawking’s talk.

• Press release from GR17 conference on Stephen Hawking’s talk
• Transcript of Hawking’s talk on black hole information loss

Judge for yourselves! At least, if you’re up on the background reading about Euclidean quantum gravity and the AdS/CFT correspondence. Thanks to Dennis Overbye of the New York Times for forwarding the material.

Update: Peter Woit has a parsing of what Hawking is trying to say. I think the most direct paragraph is probably this one:

So in the end, everyone was right, in a way. Information is lost in topologically non trivial metrics, like the eternal black hole. On the other hand, information is preserved in topologically trivial metrics. The confusion and paradox arose because people thought classically, in terms of a single topology for spacetime. It was either R4, or a black hole. But the Feynman sum over histories, allows it to be both at once. One can not tell which topology contributed the observation, any more than one can tell which slit the electron went through, in the two slits experiment. All that observation at infinity can determine, is that there is a unitary mapping from initial states, to final, and that information is not lost.

The idea seems to be that, so far as information measured at infinity is concerned, when we integrate over all possible geometries the relevant ones are those that don’t have black holes at all, merely apparent horizons. Some evidence for this point of view is adduced from AdS/CFT (the connection, first discovered by Juan Maldacena, between certain configurations of quantum gravity and certain field theories in one less spacetime dimension).

When we ultimately agree on the resolution of the information paradox, this idea may very well be part of the story. For the moment, it doesn’t seem like a very practical suggestion, to say the least; it amounts to a promise that, if only we could actually do the path integral for Euclidean quantum gravity, all the information would be preserved and end up in the outgoing Hawking radiation. It remains the case that most people are quite skeptical that we will ever make sense of the Euclidean path integral, especially in the semi-classical regime Hawking makes use of. So one way or another, there’s still a lot of work to be done!

With the release of I, Robot, everyone is talking about the terrible damage being done to the ideas of Isaac Asimov. Over at The Fulcrum, for example, Charles2 lists the three Laws of Robotics,

1. A robot may not injure a human being or, through inaction, allow a human being to come to harm.
2. A robot must obey orders given it by human beings except where such orders would conflict with the First Law.
3. A robot must protect its own existence as long as such protection does not conflict with the First or Second Law,

and wonders whether they could be applied to politics and government.

What I wonder is, what kind of lunatic thought that these laws were ever workable? Especially the first one. A robot cannot, through inaction, allow a human being to come to harm? Human beings are coming to harm all the time all over the world, and that’s only if we stick to straightforward physical harm, not to mention more subtle varieties. Every robot with these laws programmed into them would instantly launch on a frenzied quest to change the very nature of reality in order to stop all of this harm from happening. I just want something that will vacuum my floors efficiently, not save the world.

The whole point about robots (or computers more generally) is, they’re very literal-minded. They don’t know the meaning of “within reason.” When talking to each other rather than to machines, human beings are never perfectly precise about what they mean, often for good reason. That’s why we’ll always have literary critics, theologians, and the Supreme Court: to help us understand what was really being said.

I met Asimov once, when he visited my undergraduate university. They thought it would be fun to show him around the astronomy department, much to his bemusement (he was trained as a chemist). He used his advanced age as an excuse for shamelessly flirting with every attractive woman within leering distance. I wonder what he was like before his age was so advanced?

Longtime readers will attest that I am extremely dedicated to sharing my random thoughts with everyone out there in blog-land. But from time to time my jet-setting lifestyle will take me to places where internet connectivity is faint or nonexistent. To deal with this terrible possibility, we are inaugurating a new feature here at Preposterous: the guest-blogger. (I understand that bloggers elsewhere have also experimented with this idea, but it’s new for us.)

Figuring that we might as well start at the top, we are pleased to announce that our first guest blogger will be Gretchen Helfrich. Everyone in Chicago, and many public-radio listeners elsewhere, will recognize Gretchen as the host of the daily radio program Odyssey from Chicago Public Radio. (Anyone with RealPlayer can listen over the web whenever they like.) Odyssey represents exactly what you would like to hear on public radio: a spirited and in-depth examination of ideas, ranging from politics to science to the arts. Sort of like this blog, without as much whimsical self-indulgence and pictures of Godzilla. The best feature of the show is how they make every effort to generate light rather than heat, remaining interesting and entertaining while digging carefully into the issues lurking behind the topics being discussed. The opposite of the O’Reilly Factor in every way.

Gretchen will be taking the reins for about a week starting on Friday, as I’ll be traipsing through the wilds of Wyoming. Everyone play nice, now.

More old-school bands should do this. In celebration of thirty years together, Rush has come out with Feedback, an EP of cover tunes, focusing on the songs they were insprired by back in the Sixties when they were first learning rock and roll. For those of you who know or care, Rush is one of those love/hate bands; a progressive-rock power trio, they are worshipped by their fans for their fantastic musicianship, and belitted by their critics for being ponderous and pretentious. Count me as a fan. Who wouldn’t want to hear Geddy Lee sing Summertime Blues?

In honor of their anniversary, here’s a picture of Neil Peart with his drum kit (click for full glory).

Like Daniel Drezner, I find it necessary to put to rest those unfounded speculations that I will soon be drafted to run as the Republican nominee for the U.S. Senate from Illinois. Now, even on the face of it there are certain manifest obstacles that would have to be overcome. It is true, for example, that I have occasionally implied a favorable attitude towards gay marriage, questioned the existence of God, argued against building a missile defense system, poked fun at the President (also here, here, here, here, here … well, you get the point), and even said nice things about the Big Bang. I’ve also been known to consort with the enemy. Oh yes, and I’ve promised never to run for office. (Now that I think about it, anyone with a blog and a less-than-perfect amount of self-control would have a hard time not leaving such an inflammatory trail of comments that they would be instantly disqualified from any future political career.)

But I’m a believer in a strong two-party system, and the GOP in my adopted home state is kind of on the ropes these days. Democratic nominee Barack Obama has seen all of his opponents implode, has just been tapped to give the keynote address at the Democratic national convention, and is generally being given rock-star treatment by the national media. Attempts by Republicans to inject some celebrity star power of their own have fizzled, and are now becoming increasingly desperate. And, you know, I am well-educated, gainfully employed, and a practiced public speaker. They could do worse (and seem to be trying to).

Alas, it’s not to be. As much as I would love to set an exciting precedent by entering the campaign as a Republican running to the left of his Democratic opponent, I feel too strong a sense of obligation to my students and colleagues here at the University of Chicago, who frankly would be lost without me.

But if Bush does decide to dump Cheney, he has my number.